Metamath Proof Explorer
		
		
		
		Description:  Lemma for ipval3 .  (Contributed by NM, 1-Feb-2007)
       (New usage is discouraged.)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | dipfval.1 | ⊢ 𝑋  =  ( BaseSet ‘ 𝑈 ) | 
					
						|  |  | dipfval.2 | ⊢ 𝐺  =  (  +𝑣  ‘ 𝑈 ) | 
					
						|  |  | dipfval.4 | ⊢ 𝑆  =  (  ·𝑠OLD  ‘ 𝑈 ) | 
					
						|  |  | dipfval.6 | ⊢ 𝑁  =  ( normCV ‘ 𝑈 ) | 
					
						|  |  | dipfval.7 | ⊢ 𝑃  =  ( ·𝑖OLD ‘ 𝑈 ) | 
				
					|  | Assertion | ipval2lem4 | ⊢  ( ( ( 𝑈  ∈  NrmCVec  ∧  𝐴  ∈  𝑋  ∧  𝐵  ∈  𝑋 )  ∧  𝐶  ∈  ℂ )  →  ( ( 𝑁 ‘ ( 𝐴 𝐺 ( 𝐶 𝑆 𝐵 ) ) ) ↑ 2 )  ∈  ℂ ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | dipfval.1 | ⊢ 𝑋  =  ( BaseSet ‘ 𝑈 ) | 
						
							| 2 |  | dipfval.2 | ⊢ 𝐺  =  (  +𝑣  ‘ 𝑈 ) | 
						
							| 3 |  | dipfval.4 | ⊢ 𝑆  =  (  ·𝑠OLD  ‘ 𝑈 ) | 
						
							| 4 |  | dipfval.6 | ⊢ 𝑁  =  ( normCV ‘ 𝑈 ) | 
						
							| 5 |  | dipfval.7 | ⊢ 𝑃  =  ( ·𝑖OLD ‘ 𝑈 ) | 
						
							| 6 | 1 2 3 4 5 | ipval2lem2 | ⊢ ( ( ( 𝑈  ∈  NrmCVec  ∧  𝐴  ∈  𝑋  ∧  𝐵  ∈  𝑋 )  ∧  𝐶  ∈  ℂ )  →  ( ( 𝑁 ‘ ( 𝐴 𝐺 ( 𝐶 𝑆 𝐵 ) ) ) ↑ 2 )  ∈  ℝ ) | 
						
							| 7 | 6 | recnd | ⊢ ( ( ( 𝑈  ∈  NrmCVec  ∧  𝐴  ∈  𝑋  ∧  𝐵  ∈  𝑋 )  ∧  𝐶  ∈  ℂ )  →  ( ( 𝑁 ‘ ( 𝐴 𝐺 ( 𝐶 𝑆 𝐵 ) ) ) ↑ 2 )  ∈  ℂ ) |